Unloading device.



C. G. SPRADO. UNLOADIN G DEVICE. APPLICATION FILED MAB..27, 1907.

Patented Jan. 27', 1914.

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COLUMBIA PLNOGRPH CD.. WASHINGTON. D. C.

i 'niet STATS ATENT hlhll,

CARL Gr. SPRADO, OF MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE ASSIGNMENTS,

IO ALLIS-CI-IAIJMERS MANUFACTURING COMPANY, A CORPORATION OF DELA- WARE.

UNLOAIDING DEVICE.

To all whom t may concern Be it known that I, CARL Gr. SPRADO, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsim have invented a certa-in new and useful Unloading Device, of which the following is a specification. y

This invention relates to valve operating mechanism, and more specifically to valve operating mechanism used in connection with blowing engines in order to regulate the volume of air compressed by said engine according to the conditions prevailing.

Many devices and arrangements of apparatus have been devised for regulating the amount of air compressed byblowing engines according to various circumstances. lith some types of motors, as for example, gas engines and electric motors, it is desirable to have the speed of the motor remain practically constant while the amount of work which it may be called upon to perform may be varied within very Vwide limits. In using such a motor for driving a blower, it is therefore desirable to have the blower so controlled that. while the volume of air which is compressed may vary within wide limits, such variation may be eii'ected without materially changing the speed of the motor.

The drawing .which accompanies this specification and forms a part thereof illus trates an embodiment of this invention and shows a longitudinal vertical section through a horizontally disposed blowing engine tub with this invention applied thereto.

Referring to the drawing,-the numerals 1 and 2 designate the heads of the compressor tub; 3 the body of the tub, which is of the ordinary Slick type; 1l the piston; 5 the piston rod; 6 and 60 outlet valves; 7 and 70 auxiliary outlet valves; 8 the feet of the headcastings by which they are secured to and supported by foundations not shown.

The piston rod 5 is extended through each end of the cylinder and is guided by a crosshead or guide at either end 9 and 10. The front end of the piston rod is intended to be secured to the piston rod 11 of a gas engine, for example. Secured to the piston rod 5, for convenience at the crossheads 9 and 10, are the movable links 12 and 18 which are pivotally secured respectively to links 14; and 15, these links in turn being pivotally secured by pivots 16 and 17 to Specification of Letters Patent.

Application filed March 27, 1907.

Patented Jan. 2, 1914.

Serial No. 364,815.

blocks 18 and 19, said blocks being movable back and forth with respect to the blowing cylinder, as for example, by the screw-threaded shaft 2O with which said blocks 18 and 19 are in screw-threaded en-y gagement, said screw threads being shown as of opposite hands and said shaft being adapted to be rotated either by the hand wheel 21 or the rack 22 which is actuated by the spring opposed piston 23 in the cylinder 24:, which latter is in communication with the air under pressure by means of the pipe 25, said rack 22 being adapted to be engaged with a pinion 2G upon the shaft 2O or disengaged therefrom. Secured to the pivots 16 and 17 are links 27 and 28 to which, and to the links 12 and 13, are pivotally secured links 29 and 30, to which links are connected the valve stems 31 and 32 respectively of the valves 70 and 7.

The arrangement of links just described is a parallel motion means and reducing mechanism not necessarily essential to the object to he attained by this invention, but affording a convenient means for operating Jthe valves'T and 70 directly from the piston rod 5, while at the same time permitting the time of opening and closing of said valves to be varied either automatically or by hand according to the controlling circumstances. l The valves and 70 with the construction of apparatus as shown, move in the same direction as the piston 4, but their stroke is a great deal shorter than the stroke of said piston and the length of their stroke remains substantially constant notwithstanding the various positions which may be occupied by blocks 18 and 19. The ports shown in said valves may completely register with the ports l1 and 40 so that the full capacity of said ports may he available for freely discharging air to the atmosphere during a part of the stroke of the piston 4, or said ports may only partly register with ports 1-1 and 40, or they may not register at all, depending upon the positions of blocks 18 and 19.

The operation of the apparatus is as follows: Assuming the pipe 25 to be connected with the air receiver and the spring 230 to be properly tensioned so that the piston 23 will assume a definite position in the cylinder for the definite air pressure, say 75 the drawing the pressure indicated is slightly less than that desired, the engine being running sufficiently fast and with power enough so that the air pressure is constantly increasing, then with the parts in the position as shown by the drawing with the piston moving to the left as indicated by the arrow, the air is being discharged through the outlet valve G0, the auxiliary valve 70 at that end of the tub is closed and will remain closed throughout the stroke. If, now, the air pressure increases to the predetern'iined limit, the piston Q3 will be depressed, the screw-threaded shaft 20 will be rotated, and the blocks 18 and 19 .will be moved nearer to the blower, the result being that the outlet ypassages l0 and d-l will be opened during more of the stroke-of the piston si and the air can escape through said outlet passages to the atmosphere, thus preventing the air pressure from rising above the predetermined amount while permitting the speed `of the engine to remain substantially constant.

What I claim is,h

l. The combination with 4a. constant Aspeed blowing engine cylinder having inlet and outlet ports, of a piston and piston rod, an auxiliary outlet valve, and a pinned link means for automatically reducing piston -In0- tion connecting the piston rod, the auxiliary valve, and the engine frame.

2. The combination with a constant speed blowing' engine cylinder having inlet and outlet lport-s, of a piston and piston rod, an auxiliary outlet valve, a pinned link means for automatically reducing piston motion connecting the piston rod, the auxiliary val-ve, `and the engine frame, and means for shifting theiconnection between the reducing motion means along the engine frame.

3. The combination with a consta-nt speed blowing engine cylinder having inlet and outlet ports, of a piston and piston rod, an auxiliary outlet valve, a pinned link means for automatically `reducing piston motion connecting the piston rod, the auxiliary `Valve, and the engine frame, and -automatic means for shifting the connection 'between the reducing motion means along the engine frame.

4. The combination with a constant speed blowing engine cylinder having inlet and outlet ports, of a piston and piston rod, an auxiliary outlet valve, a pinned link -means for automatically reducing piston motion connecting the piston rod, the auxiliary valve, and the engine frame, and fluid pressure actuated means for shifting the connection between the vreducing motion means along the engine frame.

5. The combination with a constant speed blowing engine cylinder having inlet and outlet ports, of a pistonand piston rod, an auxiliary outlet valve, means for causing the valve to have a lcycle of motion, and means for .changing the limits of lthe auxiliary valve motion withoutichangingthe-length of its stroke.

6. The combination with a constant speed blowing engine cylinder having inlet and outlet lports, `of .a piston and piston rod, an Vuu-xiliary valve, means `for causing the valve to unload the cylinder for a part of rthe piston stroke., and Vmeans for changing the limits oi the auxiliary valve motion without changing xthe length vof `its, stroke.

.7.I-fn Acombination with a .constant speed blowing engine v.cylinder having inlet and outlet ports, ofapiston and piston rod, an auxiliary ,outlet valve, and positive connecting ymeans between said piston rod and said auxiliary valve ytor reducing the piston .motion and communicating same to said valve.

8. The combination with a `constant speed blowing `engine cylinder lhaving inlet and outlet ports, of `a piston and piston rod, an auxiliary outlet valve, :positive 4connecting means between said piston rod and said auxiliary koutlet yalve, and lmeans for adjusting said positive connecting means, whereby said auxiliary val-ve `will be reciprocated in a path parallel to `that of said piston rod in all conditions of adjustment of said positive connecting means;

In testimony whereof, I atx my signature in the presence of two Witnesses.

FRANK rE. BENNETT, ELLA BRICKELL.

Copies of this patent may be obtained :for ve cents each, addressing the Commissioner of atenta Washington, D. 0; 

